Testing device for internal combustion engines



Feb. 27, 1934. J. c. MCMURRAY TESTING DEVICE FOR INTERNAL COMBUSTION ENGINES 'Fi1ed'Aug- 25, 1933 Y by/ww Wafm rwenTor. UohnC. M'CMUTTQ ATTys'.

Patented Feb. 27, 1934 TESTING.- DEVICE Fon INTERN coMBUs'rroN ENGmEs John O. McMurray, Winthrop Center, Mass. Application August 25, 1933. Serial No. 686,820 Claims. (Cl. 175-183) This invention relates to a testing device for use in testing internal combustionengines to locate ignition trouble, knocks, side'slaps, leaking piston rings, leaking gaskets, etc.

5 The features wherein the invention resides will be more fully set forth in the following description of a selected'embodiment of my invention and will then be pointed out in the appended claims.

In the drawing: A Fig. 1 is a view illustrating Va testing device embodying myinventicn;

Fig. 2 is a section on the line 22, Fig. 1; Fig. 3 is a section on the line 3-3, Fig. 1. My improved testing device comprises a supporting base or frame, a plurality of circuit connections leading therefrom and adapted 'to be connected to the spark plugs of the internal combustion engine. each circuit connection terminating at a contact carried by the base, and a plurality of rotary switch members of novel construction by which each circuit connection may be connected to `a ground connection thereby to short circuit or cut out the corresponding spark plus. I

. In the drawing the supporting base or frame is indicated generally at 1 and it is made of suitable insulating material. Said base or frame is shown as provided with clips 2 by which it y may be clipped to the radiator rod 3 of the automobile and thus suspended in position above the .automobile engine which ls indicated in dotted lines at 4.

The base member 1 is provided with a plurality of circuit connections 5 adapted to be connected to the spark plugs 6 of the engine 4. Each circuit connection is shown as having at its end a spring clip 7 adapted to be clipped onto theend of the spark plug and for convenience in operation each spring clip is enclosed in a rubber hood or casing 8. The circuit connections 5 will, of course, be

covered with suitable insulation. The use of the hood 8 permits the clips '1 to bev readily applied to the spark plugs of the-engine while the L5 latter is operating without danger that; the person manipulating the circuit connections will receive avshock. A

Each circuit connection terminates with a contact member 10 carried by the base. These contacts are shown as balls which are received in v recessesvformed in the base 1, each ball being backed by a spring 11. Each circuit connection extends into an opening in the base 1 provided therefor and is electrically connected to the spring 1l of the corresponding contact member,

groove 16 in which the corresponding ball contact 05 10 is partially received. Each rotary element also is provided with a contact member 17 which is electrically connected with the shaft 13 and which may be brought into engagement with the corresponding ball contact 10 by swinging the handle 70 lirom the full to the dotted line position Fig. 2.

' The shaft 13 is grounded and in effect forms a grounded buss-bar. This grounding of the shaft 13 can be accomplished in various ways and as herein shown each bearing member 14 in which u' the shaft 13 is mounted extends through the base 1 and is provided with a footportion 18 secured to one of the clips 2. The shaft 13 is, therefore grounded through the bearings 14. feet 18, clips 2 and radiator rod 3. c When any operating handle 15 is in its elevated position shown in Figs. 1 and 2 the corresponding circuit connection 5 is disconnected from the ground or is open by reason of the fact A Athat the corresponding ball contact 10 has en- Sii gagement with the rotor or insulating material. When, however, any handle is turned into the dotted line position the contact 17 of the corresponding rotor 12 will be brought into engagement with the corresponding ball contact 10and 00 thereby the corresponding circuit connection 5 will be connected to the ground connection thus short circuiting the spark plug to which said circuit connection is secured.

Associated with the switch device is a neon 06 gas tube element designed for the purpose of determining the strength of the spark created by any spark plug. 'I'his gas tube element is indicated at 19 and it is mounted in an arm r20 which is pivoted at 21 to an extension 22 del00 pending from the base 1. The gas tube 19 is shown as carried in a recess in the arm 20 and said arm is provided with a sight opening 23 through which said .tube is visible. Said arm carries at its free end a contact linger 24 adapted 106 to engage any one of a numberv of contacts 25 that are carried bythe base 1 and are situated adjacent the circuit connections.

26 indicates a knurled thumb piece secured to the arm 20 and by which the latter` may be U0 handles 15 of the switch elements will all be elements in the open position. shown in Figs. 1

placed in their upright-position shown in-iull lines Figs. 1 and 2 so that each of the circuit connections 5 is disconnected from the ground.

To test the character of the spark generated by the different spark plugs the engine will be started and run at a fair speed with the switch and 2. The arm is then shifted from one to another of the contacts and the character of the flash emitted by the gas tube 19 is noted. It the iiashes produced in the gas tube 19 are bright and steady this will indicate that the spark plug nibs are properly set and that the spark plug is functioning correctly. If the ashes are not steady and bright but are dull and weak this indicates faulty ignition or improper adjustment of the spark plug nibs or some defect in the breaker points ci.' the timer or possibly in the condenser.

By thus shifting the arm 20 into engagement with the various contacts 215 while the engine is running and at the same time noting .the

character of the ashes in the gas tube 19 a test of the ignition system of the engine can be quickly and accurately made.

When the handle 15 oi. any of the switch elements 12 is thrown into horizontal position indicated by dotted lines Fig. 2 the corresponding spark plug will be cut out and the cutting out of part of the cylinders while the motor is running. on a partially opened throttle brings a compression load on the cylinders which are operating and by oscillating the different handles 15 back and forth so as to rapidly make and break the corresponding circuit connection through the ground it is possible lto quickly locate knocks, leaking valves, leaking `gaskets and other troubles in the cylinders.

The device may be constructed with any desired number of circuit connections and rotaryswitches. In the drawing I have shown four such connections which is the number of connections that would be used for testing a four-cylinder lengine. For testing an eight-cylinder engine, two devices such as shown in Fig. 1 oi!4 the drawing may be used thus providing eight circuit connections. For a six cylinder engine it would be desirable to have a device which is made with six circuit connections.

The apparatus is self-contained and is simply constructed so that it is very easily put in place. The testing involves simply manipulation of the 4arm 20 and thev handles 15.

I claim:

1.. A tester for internal combustionA engines comprising a supporting frame or base, a plurality of circuit connections leading from the base and adapted to be connected to the spark plugs of the engine, each circuit connection terminating in a contact element carried by the base, a plurality of rotary switch elements, one for each vcontact element, mounted on the base, a ground connection, each switch element adapted in one position to electrically connect the corresponding circuit connection to the ground connection and in another position to disrupt such connection, a neon gas tube and a movable carrier therefor by which said tube can be placed in ashins relation to any one o! the circuit connections.

2. A device of the class described comprising a supporting base, clips carried thereby to attach the base to a grounded support, said clips forming a grounded connection, a plurality of circuit connections leading from the base and adapted to be connected to the spark plugs of an internal combustion engine, each circuit connection terminating in a ball contact at the base, a plurality oi' independent rotary switch elements, one for each circuit connection, each element being formed of insulating material and having a contact adapted for engagement with the corresponding ball contact, each rotary switch element when in one position connecting the corresponding circuit connection to the ground connection.

3. A device for testing internal combustion engines comprising a base member, clips carried thereby for attaching the base member to a grounded support, said clips constituting a grounded connection, a plurality o! circuit connections leading from the base and adapted to be attached to the spark plugs of the engine, each circuit connection terminating in a ball contact, a supporting rod carried by the base and electrically connected to the clips and forming part of the ground connection, a plurality oi.' rotary switch elements rotatively mounted on said supporting rod, each switch element being of insulating material and having engagement with a ball contact, each switch element also having a contact element in electrical contact with said rod and which may be brought into engagement with the corresponding ball contact by a rotative movement of the switch element, and a handle extending from each switch element by which it may be turned.

- 4. A tester for internal combustion engines comprising a supporting frame or base, a plurality of circuit connections leading from the base and adapted to be connected to the spark plugs o! the engine, veach circuit connection terminating in a contact element carried by the base, a plurality of rotary switch elements, one for each contact element mounted on the base, a grounded connection, each switch. element adapted in one position to electrically connect the corresponding circuit connection to the ground connection and in another position to disrupt such connection, and a swinging arm carrying a gas tube and having a contact point which by swinging movement of the arm is brought into operative position relative to the different circuit connections. y 5. A tester for' internal combiution engines \c6mprising a supporting base, a plurality of circuit connections `leading from the base and adapted to be connected to the spark plugs ot the engine, a ground connection, a plurality ci' switch elements by which each circuit connection can be connected to the ground connection, a swinging arm pivoted'to said base, and a neon gas tube carried by said -arm and adapted by the swinging movement thereof to be brought into ashing relation to any one of the circuit connections.

JOHN C. MCMURRAY.

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D l S C L A I M E R A 1,948,882.-Jolm C. McMurray, Winthrop Center, Mass. TESTING DEVICE Fon INTERNAL CoMBUs'rroN ENGINES. Patent dated February 27, 1934. Disclaimer led December 23, 1939, by the patentee.

Hereby enters this disclaimer to claim 5 of said patent.

[ic'ial Gazette January 23, 1.940.] 'Y 

